1. Field of the Invention
The invention relates to a modular terminal, especially for locking onto a support rail, with a terminal housing, with a busbar and with at least two terminal elements for connecting at least two conductors to the busbar, on the two connection sides in the terminal housing two functional slots respectively being made and in the busbar corresponding to the first functional slot a first connection possibility for a test socket or a test plug and corresponding to the second functional slot a second connection possibility for a fixed link or a jumper being formed. In addition, the invention relates to a modular terminal block consisting of at least two modular terminals which can be locked next to one another on a support rail.
2. Description of Related Art
Electrical modular terminals have been known for decades and are used in the millions in the wiring of electrical systems and devices. The terminals are generally locked onto support rails which for their part are often located in a plurality in the switching cabinet. The terminal elements in modular terminals are mainly screw-type terminals or tension spring terminals. In addition, however, insulation piercing connecting devices or leg spring terminals can also be used.
The basic type of the modular terminal is the connecting terminal which has at least two terminal elements which are electrically connected to one another via an electrically conductive connecting bar, the busbar. In addition to this basic type, which is often called a feed-through terminal, there is a host of different modular terminal types which are matched especially to the respective application. Examples are protective-conductor terminals, isolating terminals and test terminals.
In particular, various switching, isolating and testing tasks must often be performed in modular terminals which are used in current converter measurement circuits in power generation, transmission and distribution. For this purpose, there are various accessories, such as test sockets, fixed links or jumpers, which can be attached in the modular terminals and can be connected in an electrically conductive manner to the busbar. Using fixed links potential distribution between adjacent modular terminals can be easily accomplished. Jumpers are used to electrically connect two or more adjacent modular terminals to one another as necessary so that there is the possibility of short-circuiting a connected current transformer.
One special modular terminal type which is used especially in current transformer measurement circuits or voltage transformer measurement circuits is the so-called test isolating terminal which is often also called a measurement transformer isolating terminal according to its use. In test isolating terminals the busbar consists of two component pieces which can be selectively connected to one another via a section disconnector or can be isolated from one another.
The modular terminal which underlies the invention is marketed by the assignee under the name test isolating terminal URTK 6 (see, CLIPLINE 2007 catalog, page 334, of Phoenix Contact GmbH & Co. KG). The known modular terminal, on both connection sides in the terminal housing, has two functional slots respectively and corresponding to the functional slots in the two component pieces of the busbar, each has two connection possibilities for a test socket, a test plug, a fixed link or a jumper. The connection of the aforementioned switching and testing accessories to the two component pieces of the busbar takes place by two threaded holes being formed in the component pieces of the busbar and a screw of the respective accessory being able to be screwed into the holes. This ensures secure attachment and good electrical contact-making of the respective accessory in the modular terminal or to the busbar. However, the disadvantage here is that it is relatively time-consuming to screw the respective accessory into the busbar. Moreover, with the test socket screwed in, bridging to adjacent modular terminals is only possible to a limited degree.